.\" Copyright (c) 1995
.\"	The Regents of the University of California.  All rights reserved.
.\"
.\" This code is derived from software developed by the Computer Systems
.\" Engineering group at Lawrence Berkeley Laboratory under DARPA contract
.\" BG 91-66 and contributed to Berkeley.
.\"
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.\" modification, are permitted provided that the following conditions
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.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"	This product includes software developed by the University of
.\"	California, Berkeley and its contributors.
.\" 4. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
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.Dd December 14, 1995
.Dt LOGIN 3
.Os "Linux NetKit (0.17)"
.Sh NAME
.Nm login ,
.Nm logout ,
.Nm logwtmp
.Nd login utility functions
.Sh SYNOPSIS
.Fd #include <util.h>
.Ft void
.Fn login "struct utmp *ut"
.Ft int
.Fn logout "const char *line"
.Ft void
.Fn logwtmp "const char *line" "const char *name" "const char *host"
.Sh DESCRIPTION
The
.Fn login ,
.Fn logout ,
and
.Fn logwtmp
functions operate on the database of current users in
.Pa /var/run/utmp
and on the logfile
.Pa /var/log/wtmp
of logins and logouts.
.Pp
The
.Fn login
function updates the
.Pa /var/run/utmp
and
.Pa /var/log/wtmp
files with user information contained in
.Fa ut .
.Pp
The
.Fn logout
function removes the entry from
.Pa /var/run/utmp
corresponding to the device
.Fa line .
.Pp
The
.Fn logwtmp
function adds an entry to
.Pa /var/log/wtmp .
Since
.Fn login
will add the appropriate entry for
.Pa /var/log/wtmp
during a login,
.Fn logwtmp
is usually used for logouts.
.Sh RETURN VALUES
.Fn logout
returns non-zero if it was able to find and delete an entry for
.Fa line ,
and zero if there is no entry for
.Fa line
in
.Pa /var/run/utmp .
.Sh FILES
.Bl -tag -width /var/run/wtmp -compact
.It Pa /dev/\(**
.It Pa /etc/ttys
.It Pa /var/run/utmp
.It Pa /var/log/wtmp
.El
.Sh SEE ALSO
.Xr utmp 5
